Diurnal variations of tropical cyclone precipitation in the inner and outer rainbands

Abstract

Abstract Using 15 years (1998–2012) of satellite‐measured precipitation data and tropical cyclone (TC) information, this study estimates the diurnal variations of TC precipitation in its inner core and outer rainbands. It is found that for both weak (tropical storms to category 1 TCs) and strong (categories 2–5 TCs) storms over all six TC basins, the TC precipitation reaches its daily maximum in the morning, but the mean rain rate and diurnal variations are larger in the inner core than in the outer rainbands. With increasing radial distance from the TC center, the diurnal amplitude of precipitation decreases, and the peak time appears progressively later. The outward propagation of diurnal signals from the TC center dominates as an internal structure of the TC convective systems. For all basins examined, the diurnal precipitation maximum within the inner core of a strong storm occurs earlier than the maximum observed in non‐TC precipitation; the same result is not found for the outer rainbands. In the North Atlantic, the diurnal variations of TC precipitation in weak storms are much weaker than those in other basins, and the TC precipitation in strong storms shows a semidiurnal cycle in the inner core while exhibiting a clear diurnal cycle with a peak around noon in the outer rainbands.